Image transfer apparatus with CEC communication function

ABSTRACT

A video transmitting apparatus including: a first register that is set when receiving a CEC (Consumer Electronics Control) message which is transmitted by a video signal source and is reset in response to a leading edge of a predetermined voltage that is supplied from said video signal source; and a second register which reads an EDID (Extended Display Identification Data) of a video displaying apparatus, is set when a decision is made that said video displaying apparatus is a predetermined video displaying apparatus, and is reset when a state where an HPD (Hot Plug Detect) is in a state of low has continued for a predetermined period of time or longer, wherein when both of said first and second registers have been set, a determination is made that said video signal source, said video transmitting apparatus, and said video displaying apparatus have been connected.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation application of U.S. Ser. No.15/494,952, filed Apr. 24, 2017, which is a continuation of U.S. Ser.No. 13/914,717, filed Jun. 11, 2013, now U.S. Pat. No. 9,674,474, whichis a continuation application of U.S. Ser. No. 12/326,930, filed Dec. 3,2008, now U.S. Pat. No. 8,462,843. This application relates to andclaims priority from Japanese Patent Application No. 2007-316528, filedon Dec. 7, 2007. The entirety of the contents and subject matter of allof the above is incorporated herein by reference.

BACKGROUND OF THE INVENTION

The invention relates to a video signal transmitting apparatus forinputting a video signal output of a video signal source, processing thevideo signal, and outputting to a displaying apparatus.

An example of a video signal transmitting apparatus forvideo-compressing a video signal of a video signal source and,thereafter, radio-transmitting to a displaying apparatus has beendisclosed in JP-A-2004-165921.

As a digital video interface between apparatuses, there is an HDMI(High-Definition Multimedia Interface) disclosed in “High-DefinitionMultimedia Interface Specification, Informational Version 1.0, HDMI,LLC, USA, 2003/9/4”. In the HDMI, a CEC (Consumer Electronics Control)has been determined as a communication specification between theapparatuses using lines in an HDMI cable. An example of making controlbetween the apparatuses by using a CEC message for transferring controlinformation and apparatus information of the connected apparatus in theCEC standard has been disclosed in JP-A-2007-214952.

In the HDMI, such a technique that the video signal source reads EDID(Extended Display Identification Data) information showing displayability and specification of a video displaying apparatus and selects aformat of an output video signal has been disclosed in “A DTV Profilefor Uncompressed High Speed Digital Interfaces CEA-861B, ConsumerElectronics Association, USA, May 2002”. Such a technique that as timingwhen the signal source reads the EDID information, an HPD (Hot PlugDetect) signal in which a state where the cable has been connected isshown by a logic level “H” is used and such timing is set to timingafter the logic level was changed from “L” to “H” has been disclosed in“High-Definition Multimedia Interface Specification, InformationalVersion 1.0, HDMI, LLC, USA, 2003 Sep. 4”. By using those mechanisms,the specification of the video displaying apparatus can be transferredto the video signal transmitting apparatus and the specification of thevideo signal transmitting apparatus can be transferred to the videosignal source.

SUMMARY OF THE INVENTION

In the case of radio-transmitting the video signal, since a transmittingspeed is often lower than that of the wired connection, as disclosed inJP-A-2004-165921, a transmission amount is reduced by using videocompression and the signal is transmitted. In order to raise a videocompression ratio while keeping high picture quality, it is necessary toexecute an advanced video process before the video compression and toalso execute a video process for compensating a picture qualitydeterioration peculiar to the video compression in the case of decodingthe signal on a reception side.

The video process before the video compression is executed by a videoprocessing unit provided for the video signal source and the videoprocess after the decoding is executed by a video processing unitprovided for the displaying apparatus, so that the video signaltransmitting apparatus which plays a role of the radio transmission canexecute the advanced video compression. To make such a processing methodfunction, a predetermined video signal source, the video transmittingapparatus, and the video signal displaying apparatus have to beconnected.

As shown in “A DTV Profile for Uncompressed High Speed DigitalInterfaces CEA-861B, Consumer Electronics Association, USA, May 2002”,the HDMI has a mechanism for directly transferring the specification ofthe video displaying apparatus to the video transmitting apparatus bythe mechanism of EDID. To transfer the specification of the video signalsource to the video transmitting apparatus, it is considered to use aphysical address included in the CEC message.

However, when the CEC message is transmitted in a wireless manner, thereis a problem disclosed in JP-A-2004-165921 and a special mechanism isneeded. Therefore, there is a case where the user does not want toinstall the CEC message. Further, in order to rapidly know a change inapparatus and make optimum control, it is necessary not only to read theEDID at the timing of the HPD and obtain the apparatus specification inresponse to the arrival of the CEC message but also to detect the timewhen the connecting state is cancelled. However, a specific mechanismfor it is not shown.

It is an object of the invention to solve the foregoing problems and toprovide a video transmitting apparatus which can promptly and certainlydetect without an error a fact that a predetermined video signal sourceand a predetermined displaying apparatus have directly been connected toan input and an output of the video transmitting apparatus,respectively.

The invention comprises a first register that is set when receiving aCEC message which a video signal source reads an EDID of a videotransmitting apparatus and issues and is reset in response to a leadingedge of 5V that is supplied from the video signal source and a secondregister which reads an EDID of a video displaying apparatus, is setwhen it is decided that the video displaying apparatus is apredetermined video displaying apparatus, and is reset when a statewhere an HPD is in a state of “L” has continued for a predeterminedperiod of time or longer and is characterized in that only when both ofthe first and second registers have been set, it is determined that thepredetermined video signal source, the video transmitting apparatus, andthe video displaying apparatus have directly been connected.

Further, there is such a second feature that in the case where the firstregister is a register which is initialized when a power source is OFF,after the state change of the first register, if such a state continuedfor a predetermined time, the state of the first register is stored intoa nonvolatile memory, the power source of the video transmittingapparatus is turned off, and the first register is initialized, and whenthe power source has been turned on again, the state of the nonvolatilememory is returned to the first register.

In the case where the video transmitting apparatus is a radio apparatus,since a video process for converting into a video signal which can beeasily and highly video-compressed can be executed in the video signalsource, the video transmitting apparatus can execute a high compressionvideo process, and the video displaying apparatus can execute a videoprocess for suppressing a picture quality deterioration that is peculiarto a high compression video image, the high picture quality can berealized within a range of a limited transmission speed. The inventionalso has such a feature that when either the video signal source or thevideo displaying apparatus is not a predetermined apparatus, if the highpicture quality realizing process is executed, since there is a casewhere it results in a reverse effect, a standard video compressingprocess which does not need special video processes before and after thehigh picture quality realizing process is executed.

There is such a feature that since the invention functions as a videotransmitting apparatus for transmitting a specific CEC message only whenthe predetermined video signal source and the video displaying apparatusare connected to a radio transmission side and a radio reception sideand stopping the transmission of the specific CEC message to otherapparatuses, it is possible to prevent an influence such as a busneck orthe like due to the transmission of the specific CEC message from beingexerted on a CEC general apparatus.

Since the video transmitting apparatus to which the invention is appliedcan detect, at accurate timing, that the predetermined video signalsource and the video displaying apparatus have respectively directlybeen connected to its input/output terminals, a video transmittingsystem in which the optimum video process has been executed to each ofthem can be constructed and a special control signal transmittingfunction can be provided.

Other objects, features and advantages of the invention will becomeapparent from the following description of the embodiments of theinvention taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a video system comprising a videotransmitting apparatus, a video signal source, and a video displayingapparatus according to the first and second embodiments of theinvention;

FIG. 2 is a diagram showing a control sequence in the first embodimentof the invention;

FIG. 3 is a state transition diagram of the video transmitting apparatusin the first embodiment of the invention;

FIG. 4 is a state transition diagram of the video transmitting apparatusin the second embodiment of the invention;

FIG. 5 is block diagram of a video system comprising a videotransmitting apparatus, a video signal source, and a video displayingapparatus according to the third embodiment of the invention.

DESCRIPTION OF THE EMBODIMENTS

A video transmitting apparatus in the invention will be describedhereinbelow with reference to the drawings. In the followingembodiments, similar component elements are designated by the samereference numerals.

[Embodiment 1]

FIG. 1 is a block diagram showing a construction of a video displaysystem 1 according to the invention. In FIG. 1, a video transmittingapparatus 15 is constructed by a radio transmitting unit 12 and a radioreceiving unit 13 and transmits a video signal which is outputted from avideo signal source 11 to a video displaying apparatus 14.

First, a flow of the video signal will be described. The video signalsource 11 executes a predetermined scaling process and a picture qualityimprovement signal process to the video signal formed in a video/audiosignal forming portion by a video signal processing portion 115 and,thereafter, the signal is transmitted from a TMDS transmitting portion114 to a TMDS receiving portion 124 through a line 103. An output of theTMDS receiving portion 124 of the radio transmitting unit 12 is encodedby a video compressing portion 126, a video data amount is compressed,and thereafter, the compressed signal is transmitted from a radiotransmitting portion 127 to a radio receiving portion 136 of a radioreceiving unit 13 by a radio wave 104.

An output of the radio receiving portion 136 is decoded into anon-compression video signal format by a video decoding portion 137,subsequently, noises or the like caused by the video compression aresuppressed in a video processing circuit 135, and thereafter, the outputis transmitted from a TMDS transmitting portion 134 to a TMDS receivingportion 144 of the video displaying apparatus 14 through a line 107. Anoutput of the TMDS receiving portion 144 is inputted to a videoprocessing portion 145, is subjected to a signal process according tocharacteristics of a displaying portion 147, and thereafter, is suppliedto the displaying portion 147 and displayed.

Through lines 102 and 106, EDID reading portions 113 and 133respectively read out data in EDID storing portions 123 and 134 in whichthe data showing specifications of the radio transmitting unit 12 andthe video displaying apparatus 14 has been stored. Owing to such amechanism, the video signal source 11 and the radio receiving unit 13can know that the predetermined radio transmitting unit 12 and the videodisplaying apparatus 14 have directly been connected, respectively.After that, through lines 101 and 105, by using CEC message exchangingfunctions 111 and 121, 131, and 141, the video signal source 11 and theradio receiving unit 13 notify the radio transmitting unit 12 and thevideo displaying apparatus 14 that the predetermined video signal source11 and the radio receiving unit have been connected, respectively,thereby recognizing a fact that the system has a special systemconnecting configuration in which the predetermined video signal source11, the video transmitting apparatus 15, and the video displayingapparatus 14 have directly been connected. When such a recognition isestablished, the video signal processing portion 115 of the video signalsource 11 plays a role of such a pre-process as to raise a videocompressing efficiency and the video processing portion 145 of the videodisplaying apparatus 14 suppresses, for example, mosquito noises or thelike which are peculiar to the video compression, and integrated highpicture quality can be provided.

FIG. 2 is a diagram showing a control sequence among the video signalsource 11, radio transmitting unit 12, radio receiving unit 13, andvideo displaying apparatus 14 in the above embodiment. FIG. 3 is adiagram showing a state transition of the radio transmitting unit 12 (inFIG. 3, it is abbreviated and displayed as Tx) on the left side and astate transition of the radio receiving unit 13 (in FIG. 3, it isabbreviated and displayed as Rx) on the right side.

The grasping operation of the special system connecting configuration inthe embodiment of FIG. 1 will be described hereinbelow with reference toboth of the state sequence diagram of FIG. 2 and the state transitiondiagram of FIG. 3.

After a power source was turned on, the radio transmitting unit 12obtains a connecting state before the power source is turned off from anonvolatile memory 129 and copies into a first register 128 (311 in FIG.3). After that, the unit 12 waits until the video signal source 11starts to supply a +5V power source of DDC (312 in FIG. 3). In responseto the start of the supply of +5V of DDC, the first register 128 isreset and, at the same time, “H” is applied to the HPD and the read-outof the EDID storing portion 123 is permitted (211 and 212 in FIG. 2, 313in FIG. 3). The EDID reading portion 113 of the video signal source 11reads out the data from the EDID storing portion 143 (213 in FIG. 2).When it is determined from a predetermined manufacture's name, productmodel number, and the like that the video signal source is a videosignal source having a function for assembling a predeterminedconstruction, the EDID reading portion 113 notifies the radiotransmitting unit 12 of such a fact by a CEC message (214 in FIG. 2, 314in FIG. 3) and sets the data in the register 128 (315 in FIG. 3).

Just after the turn-on of the power source, the radio receiving unit 13resets a second register 138 (321 in FIG. 3) and supplies DDC +5V to thevideo displaying apparatus 14 (221 in FIG. 2, 322 in FIG. 3). Bydetecting a change to HPD=“H” shown by the video displaying apparatus14, the EDID reading portion 133 reads data in the EDID storing portion143 of the video displaying apparatus 14 (223 in FIG. 2, 323 in FIG. 3).When it is determined that the video displaying apparatus is apredetermined video displaying apparatus, the EDID reading portion 133sets the second register 138 (324 in FIG. 3).

When HPD=“L” in the case where the connection of the radio receivingunit 13 and the video displaying apparatus 14 is disconnected, thespecification of the video displaying apparatus is changed, or the like,the second register 138 is reset (321 in FIG. 3). The steps of 321 to324 in FIG. 3 are repeated hereinbelow. In this instance, when a periodof time of HPD=“L” is so short to be within, for example, about 2seconds, it is also possible to construct in such a manner that thesecond register is not reset but the setting state is held and thesetting/resetting operation is executed according to a result of thereading of the EDID, thereby avoiding a short state change.

A fact that both of the first register 128 and the second register 138have been set is recognized in common in the video transmittingapparatus 15 by mutually notifying the states by the radio transmittingunit 12 and the radio receiving unit 13 (215 in FIG. 2), and whether ornot the system has the special system configuration can bediscriminated.

If the power source of the video signal source is OFF when the powersource of the video transmitting apparatus is turned on, DDC +5V is notsupplied and an unknown state continues as a connecting state. To avoidsuch a situation, the nonvolatile memory is used so as to store thestate of the register 128 just before the turn-off of the power source.

Since it is generally known that the number of erroneous writingoperations increases with an increase in the number of rewriting timesof the nonvolatile memory, as a measure for reducing the number ofrewriting times, if the writing operation is started only in the casewhere the state of the first register 128 differs from the stored statein the nonvolatile memory for a predetermined time (for example, 30seconds) or more, the reliability can be improved. By the aboveoperation, when it is determined that the predetermined video signalsource, video transmitting apparatus, and video displaying apparatushave directly been connected, the video transmitting apparatus 15 raisesa compression ratio of the video compressing portion 126, allows thevideo signal processing portion 115 of the video signal source 11 toexecute the pre-process by the CEC message so that a video compressionratio can be easily raised, and allows the video processing portion 145of the video displaying apparatus 14 to execute a filtering process forreducing the noises which are peculiar to the video compression, so thatthere is such an advantage that the video transmission with the highpicture quality can be performed.

It is also possible to construct in such a manner that when it isdetermined that the predetermined video signal source, videotransmitting apparatus, and video displaying apparatus have directlybeen connected, the exchange of a special CEC message necessary for theinterlocking of the high picture quality realizing video processes, theinterlocking of the menu displays, the interlocking of the apparatusstates such as power ON/OFF, and the like among those three apparatusesis permitted. When the above direct connection is not confirmed, if sucha special CEC message is outputted, there is a possibility that itbecomes a CEC busneck and exerts an influence on other CEC messagecontrol. By confirming the above direct connection, there is an effectof preventing such an influence.

Since a problem such as a timing delay or the like is liable to occur atthe time of the radio transmission of the CEC message, the CEC messagetransmission dares to be stopped and the CEC transmitting function canbe used only at the time of the direct connection.

[Embodiment 2]

An embodiment using a state transition diagram of FIG. 4 in place of thestate transition diagram of FIG. 3 in the video transmitting apparatusshown in the video system block diagram of FIG. 1 is shown.

It is an object to reduce the surplus CEC message transmission when theCEC message is stopped in the case where the video signal source, videotransmitting apparatus, and video displaying apparatus are not in thepredetermined direct connecting state. The same operation portions asthose in the state transition diagram of FIG. 3 are designated by thesame reference numerals and their operation explanation is omitted.Additional portions will be described hereinbelow also with reference toFIG. 1. If such a rule that when the predetermined video signal source11 outputs the CEC message, DDC +5V is certainly supplied ispreliminarily determined, in the case where the radio transmitting unit12 receives the message before DDC +5V is supplied in the state 312, itis possible to determine that the predetermined video signal source isnot connected. Therefore, even in the case where the first and secondregisters were set and the CEC message transmission has been permitted,a CEC communicating portion 121 resets the first register 128 (411 inFIG. 4) without making a response and continues the DDC +5V standbystate 312.

In the case where the first and second registers were set and the CECmessage transmission has been permitted in the state 312, if the CECmessage is sent to a CEC communicating portion 131 of the radioreceiving unit 13, it is radio-transmitted to the radio transmittingunit 12 and transferred from the CEC communicating portion 121 to a CECcommunicating portion 111 of the video signal source 11 (state 412 inFIG. 4). The transferring operation is repeated a predetermined numberof times (twice in FIG. 4), thereby enabling the CEC message to becertainly transferred. Also in order to prevent a surplus CEC commandfrom being issued, it is also possible to set so that the CEC message isnot automatically transmitted again even in the case where the CECcommunicating portion 111 cannot receive it.

The radio receiving unit 13 is also additionally provided with such afunction that if the predetermined EDID cannot be read out for the state324 in FIG. 3, the register is reset.

The case where the video transmitting apparatus for transferring the CECcommand only in the case of the combination of the predetermined videosignal source, video transmitting apparatus, and video displayingapparatus erroneously transmits the surplus CEC message as mentionedabove can be suppressed.

[Embodiment 3]

A system block diagram according to the third embodiment of theinvention is shown in FIG. 5. The same component elements as those inFIG. 1 are designated by the same reference numerals. Reference numeral16 denotes a video transmitting apparatus with an audio processingfunction. An audio processing portion 167, a speaker 168, and the likeare connected to the video transmitting apparatus. After the directconnection of the predetermined video signal source, video transmittingapparatus, and video displaying apparatus was detected, the interlockingoperations among the directly connected apparatuses are realized on thebasis of a predetermined operating procedure.

As an example of those interlocking operations, such an application thata powerful scene is detected in the video process and an audio processis interlocking-controlled according to the scene or the like isconsidered. There is also such an application that the stereoscopicaudio reproducing and video display are executed in the case of acombination in which the video signal source has stereoscopic videocontents, the video transmitting apparatus with the audio processingfunction can reproduce a stereoscopic sound, and the video displayingapparatus can display a stereoscopic video image.

In a video transmitting apparatus having the radio video transmittingfunction or the like, there is such an advantage that a videotransmitting function of high picture quality and a high efficiency inthe case where the predetermined video signal source and the videodisplaying apparatus are combined and a standard video transmittingfunction in combinations other than the predetermined combination can beproperly switched.

There is such an advantage that the special control signal transmittingfunction can be provided only in the case where the predetermined videosignal source and the video displaying apparatus are combined.

The video transmitting apparatus according to the invention canaccurately discriminate the combination of the predetermined videosignal source and the video displaying apparatus and can realize thehigh picture quality radio video transmission, the special controlsignal transmitting function, and the video signal process.

It should be further understood by those skilled in the art thatalthough the foregoing description has been made on embodiments of theinvention, the invention is not limited thereto and various changes andmodifications may be made without departing from the spirit of theinvention and the scope of the appended claims.

The invention claimed is:
 1. A radio transmitting system fortransmitting and receiving a video signal, comprising: a radiotransmitter configured to wirelessly transmit the video signal; a radioreceiver configured to wirelessly receive the video signal from theradio transmitter; a video signal source coupled to the radiotransmitter through a first HDMI (High Definition Multimedia Interfacecable; and a video display apparatus coupled to the radio receiverthrough a second HDMI cable, wherein the radio transmitter is furtherconfigured to determine whether the video signal source has a CEC(Consumer Electronics Control) communication function or not; whereinthe radio receiver is further configured to determine whether the videodisplay apparatus has the CEC communication function or not; wherein,when the radio transmitter determines that the video signal source hasthe CEC communication function and the radio receiver determines thatthe video display apparatus has the CEC communication function, theradio transmitter wirelessly transmits the CEC message received from thevideo signal source via the first HDMI cable to the radio receiver andthe radio receiver wirelessly transmits the CEC message received fromthe video display apparatus via the second HDMI cable to the radiotransmitter; wherein, when the radio transmitter determines that thevideo signal source does not have the CEC communication function or theradio receiver determines that the video display apparatus does not havethe CEC communication function, the radio transmitter does not transmitthe CEC message received from the video signal source via the first HDMIcable to the radio receiver and the radio receiver does not transmit theCEC message received from the video display apparatus via the secondHDMI cable to the radio transmitter.
 2. The transmitting systemaccording to claim 1, wherein the radio transmitter includes a firstcontroller configured to determine whether the video signal source hasthe CEC communication function or not, and wherein the radio receiverincludes a second controller configured to determine whether the videodisplay apparatus has the CEC communication function or not.
 3. Thetransmitting system according to claim 2, wherein the first controlleris configured to determine whether the video signal source has the CECcommunication function or not based on a communication with the videosignal source via the first HDMI cable, and the communication isperformed based on an EDID (Extended Display Identification Data) of theradio transmitter, and wherein the second controller is configured todetermine whether the video display apparatus has the CEC communicationfunction or not based on an EDID (Extended Display Identification Data)received from the video display apparatus via the second HDMI cable.